Trans & Torque converter Flush Q&A - Also Dr Tranny

[97Suburban]

Hello again!!

about maybe 6 years ago, my local family business trans & garage had me purchase 2 tubes of Dr Tranny and Dextron III fluid and trans filter, and he manually flushed the trans and torque converter, and then during the refill, he added 2 tubes of Dr Tranny anti shutter treatment, and it works great!!

** oh, also he did replace 1 or 2 selenoids, but he said the selenoids and full fluid flush and Dr tranny does the job for scores of cars. What do you know about this solution???????????

So it is that time again, maybe 2 to 3 years and the shutter happens again when heading up and hill on rural roads, where the trans shutters i think with it downshifts....

So i am getting ready for a 14 hour trip down south for a few days, not towing, just a trip, and i want to make sure the trans is fresh and healthy.

Any suggestions or thoughts?
Thanks folks, kudo's for the help!!

[Dvldog8793]

Don't know anything about the DR Tranny stuff.
But...Most trans shops can "flush" the system without replacing the filter. Personally, I do both. I will drop the pan and replace the filter then top off with fluid and take it to the shop for the flush. Normally the flush is about $100. If the shop does the filter change it brings the price up to about $250.
Good luck.

[DmaxMaverick]

Unless you have the means to collect, store, then dispose of the waste fluid, it's better to just eat the cost of a flush at the shop. Otherwise, it can be done for "free" in your driveway, in an hour or less. Most often, it's just best to just do a drain/filter/fill and be done with it. Unless you have burned or contaminated fluid, a flush isn't gaining you anything on a high-miler.

I don't know anything about the Dr Tranny stuff. I use/recommend Trans-Medic fluid conditioner. It does the same think you describe the other stuff does. Once the tranny starts to shutter, it's time for overhaul. Anything you do to "cure" the shutter is borrowing time. Some work for a hundred thousand miles, others for 20. Out-of-town tranny overhauls are never convenient.

[97Suburban]

To do it myself,

I guess use 2 large pans and suck from one and dump into another while running??? any dangers i need to watch out for?
How much pressure , does it spray like mad if i put the output line into a 5 gal bucket to catch the old and use a super clean pan to suck the new fluid from?

Should i mix the dr tranny in the new fluid pan??

NAPA sells Dr Tranny (this guy loves it and i have used it two times now and he always uses for our local region, they swear by it )


My local family owned trans & garage team (4 boys and a father team, one fellow has been rebuild trans for maybe 25 years+ and always good with the locals) had me purchase 2 tubes of Dr Tranny and Dextron III fluid and trans filter, and he manually flushed the trans and torque converter, and then during the refill, he added 2 tubes of Dr Tranny anti shutter treatment, and it works great!!

So i do this every 2 to 3 or 4 years when the shutter returns....


Thanks in advance for all your help, great forum!!!!

[DmaxMaverick]

It isn't that complicated. Search the 2001+ powertrain forum for "allison flush", and you'll find a couple posts with the full, detailed instructions.

No, you do not need 2 containers, to fill and flush at the same time. In short, you'll fill it, then let the engine idle to push out the old fluid, and repeat as necessary to replace the volume of fluid. All this AFTER a normal service. Flushing is in addition to and after a normal service.

The fluid volume is fairly high, but nothing that'll blast out of a 5 gallon bucket. Do secure the line to the bucket, or it can jet out. You can either access the line at the cooler, or at the tranny, whichever is easiest for you (I recommend using the cooler return line at the tranny, for the most thorough flush). Use a section of hose that will fit as tightly as possible to the cooler line. A secure fitting is not necessary, it just has to stay in place and run downhill to the bucket. You'll need about 16-18 qts. of fresh fluid, which includes the amount needed for the initial service.

[DmaxMaverick]

Here's a thread that covers a flush. This is for the Allison tranny, but the basics are the same:

http://www.thedieselpageforums.com/tdpforum/showthread.php?t=29507

[97Suburban]

is there a flush for the 4L80E somewhere?